Conventional panels used in aircraft are typically uniform in cross-sectional strength, and are not optimized for part installations. As a result, to provide structural improvement to panels, the only option is to bond a doubler or wet-lay-up support on the back of the panel. The prior art for thermoformable liner materials focused on light weight scrim added to the bottom of the layers to create a support for material during the forming process. The scrim is often not considered structural and is in many ways a sacrificial layer, as it cannot stretch during the forming process and tears as needed in molding. The present invention allows for discrete stiffeners or reinforcement layers to be imbedded into a sheet during the calendaring paper process. As the fiberglass or carbon reinforcement is not continuous, it allows for the material to properly stretch and form to shape.
In conventional panels, if an attachment point in the panel (e.g., an edge) requires six layers for proper support, the entire panel is made of six layers. Because the center of the panel does not include any attachment points, the center of the panel may be sufficiently strong with only four layers. However, a conventional panel in this situation would still be made with six layers, thereby adding unnecessary weight. The present invention solves this issue.